The invention relates to foam insulated water heaters, and more particularly to an apparatus for sealing foam insulated water heaters.
A conventional foam insulated water heater includes a water tank having therein at least one opening. An internally threaded spud is welded or otherwise secured to the outer surface of the tank in alignment with the tank opening. An outer jacket surrounds the tank and has therein an opening aligned with the spud. A fitting extends through the opening in the outer jacket and is threaded into the spud. The fitting is adapted to be connected to a pipe or other component communicating with the interior of the tank via the spud.
It is known in the art to inject foam into the space between the outer jacket and the tank in order to insulate the tank. During injection of the foam, it is desirable to prevent the foam from flowing out of the opening in the outer jacket. To this end, it is known to connect to the spud a sealing apparatus which provides a seal between the spud and the jacket. See, for example, U.S. Pat. No. 5,117,810.